Our bodies and brains run on glucose, a simple sugar produced by the digestion of carbohydrates. The body’s ability to use glucose depends on the hormone insulin, which is produced by the pancreas. Blood sugar levels naturally rise after meals, but insulin from a healthy pancreas keeps these levels within a narrow range. In diabetes, however, this balance is disrupted because either the body loses its ability to respond to insulin or the pancreas loses its ability to produce insulin. Too much or too little glucose in the bloodstream can damage blood vessels in the kidneys and eyes, as well as nerve cells; acute disruptions of the insulin/glucose balance can be life threatening. Blood and urine tests can determine whether someone is diabetic or pre-diabetic. Diabetes is looming as a major public health concern; an estimated 25 million people in the U.S. have diabetes, with more than a quarter of them undiagnosed.